In the electronics industry, as products such as cell phones and camcorders become smaller and smaller, increased miniaturization of integrated circuit (IC) packages has become more and more critical. At the same time, higher performance and lower cost have become essential for new products.
One conventional integrated circuit package includes a wire bond die stacked on a flip chip die on a substrate. Bonding fingers are located outside the footprint of flip chip die on the substrate. A resin, which fills the gap between the flip chip die and the substrate, also extends beyond the footprint of the die in a resin fillet or bleed.
The bonding fingers must be outside the resin fillet otherwise electrical wires from the wire bond die cannot be connected to the bonding fingers because the electrical wires cannot be bonded through the resin. This means that the electrical wires must connect beyond the resin fillet and also means that the package size cannot be decreased beyond a certain point.
The typical size of the resin fillet is about 1.5-3 mm, resulting in a lateral package size increase of 3-6 mm due to the resin fillet on both sides of the die. For a nominal package size of 12×12 mm, this would result in a package size increase of 25-50% and an increase in the package footprint (area) of 50-100% over what it would be if it were possible to connect within the resin fillet.
However, no way has been found to connect within the resin fillet due to the difficulty of forming reliable conductive bonds through a resin while a need still remains for an integrated circuit package system having a reduced package size. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.